Health Risk Assessment of Natural Background Radiation in Residents of Khorramabad, Iran

Introduction Radioactive materials naturally exist in the world. Indeed, approximately 82% of humanabsorbed radiation doses, which are out of human control, arise from natural sources of radiation including cosmic, terrestrial, and exposure through inhalation or ingestion. Thus, the aim of the present study was to estimate health risk, as well as the effective and organ doses from naturally occurring background radiation in residents living in the vicinity of Khorramabad, Iran. Materials and Methods This crosssectional study was carried out in Khorramabad, Iran. The measurements were performed using GeigerMuller detector (RDS110) during daylight from April to June, 2015. The natural gamma radiation measurements were made both indoor and outdoor across five regions of Khorramabad (north, south, west, east, and center). Results The estimated mean absorbed dose rate in outdoor and indoor zones were 0.09±0.024 and 0.117±0.032 mSvy^-1, respectively. Additionally, the mean annual effective dose was calculated as 0.69±0.19 mSvy^-1, while the estimated health risk probability was 0.0345%. Conclusion The average annual effective dose arising from gamma background radiation was higher than global values. Therefore, more studies are required to examine the relationship between radiationinduced effects and the natural background radiation level in Khorramabad.